1. Field of the Invention
The present invention relates to the field of design of electronic circuits, and more specifically to a method and apparatus for reducing line/load regulation problems in switching regulators.
2. Related Art
Regulators generally refer to components which receive a potentially varying voltage or current signal (unregulated signal) as input and generate constant voltage or current signals (“regulated signal”) as output to other components of a system. Such regulated signals are generally required as input signals for the operation of such other components.
Switching regulators are a type of regulators which generate regulated signals by operating switches on and off. In general, in switching regulators, the strength of the generated regulated signals is controlled by turning various switches on and off, and thus the desired constant strength of regulated signal is achieved by controlling the duration of on state and duration of off state of the switches.
One recognized problem with generating regulated signal is that the strength of the regulated signal may not remain at desired constant strength under various operating conditions and the resulting changes may affect accurate performance of various components operating using the regulated signal.
One of the operating conditions that causes changes in the desired constant strength of the regulated signal is the variations in un-regulated signals provided as an input to the switching regulators. A parameter “line regulation” generally provides a measure of such variation and may be computed as the ratio of change in output signal for a corresponding change in input signal. Ideally, the line regulation value needs to equal 0.
Another operating condition that causes changes in the desired constant strength of the regulated signal is the variations in the load (power drawn by the components receiving the regulated signal as input). A parameter “load regulation” provides a measure of such variation and may be computed as the ratio of change in output signal due to corresponding change in the load. Again, the load regulation value also ideally needs to equal 0.
It is generally desirable that the regulated signal have a pre-specified (desired) strength for accurate performance of various components. What is therefore needed is a switching regulator providing a regulated signal having desired constant strength (voltage or current) while meeting at least some of the operating conditions noted above.